My gti had/has a noisy release bearing sound so i replaced the clutch flywleel and bearing and after putting it back together it was still there, all LUK parts same as factory. There was a bit of play on the gearbox input shaft so its looking like the gearbox bearings are gone, does the same rattly at idle untill pressing the clutch in and wines when driving.
Get it back to the garage expensive bill to do yourself.